test more complex properties

src/index.ts

@@ -13,12 +13,19 @@ export function over<T>(name: string, strategy: Arbitrary<T>, suite: Suite<T>):
         return new Promise((res, rej) => {
           const result = check(property(strategy, (t) => test.call(ctx, t)));
           if (result.failed) {
+            console.log(result);
             if (result.counterexample !== null) {
-              const examples = result.counterexample.join(',');
+              const examples = result.counterexample.map(it => {
+                if (typeof it === 'string' && it.length === 0) {
+                  return "''";
+                } else {
+                  return it;
+                }
+              }).join(',');
               const error = `failed after ${result.numRuns} runs and ${result.numShrinks} shrinks, failing on: ${examples}`;
               rej(new Error(error));
             } else {
-              rej(new Error('failed without counterexample'));
+              rej(new Error(`failed after ${result.numRuns} runs and ${result.numShrinks} shrinks, without counterexamples`));
             }
           } else {
             res();

test/TestOver.ts

@@ -1,4 +1,4 @@
-import { integer, uuid } from 'fast-check';
+import { integer, lorem, tuple, uuid } from 'fast-check';
 
 import { over } from '../src/index';
 
@@ -19,4 +19,16 @@ describe('some foo', () => {
       return id[9] !== 'a';
     });
   });
+
+  over('even numbers', integer().filter(n => n % 2 === 0), (it) => {
+    it('should be even', (n: number) => {
+      return n % 2 === 0;
+    });
+  });
+
+  over('mapped properties', tuple(lorem(), integer()).map(([a, b]) => a.substr(b)), (it) => {
+    it('should have content', (text: string) => {
+      return text.length > 0;
+    });
+  });
 });